We can explain as follows. The brachos until פסוק ט relate to brachos that Hashem gives to the natural running of the world. The nature of the world is that when there is sin, it makes a blemish in Shomayim which in turn causes great damage down here on earth [as discussed at length in Nefesh Hachaim, Derech Hashem and many other sefarim]. So here the Torah is telling us that if we erase this blemish through "אם בחוקתי תלכו" - going in Hashem's statutes, nature will be restored to its more healthy and well functioning state in which there will be rain at the proper time "ונתתי גשמיכם בעתם". It is called "גשמיכם" - Your rain, because it relates to nature which was essentially given over to man, as it says "והארץ נתן לבני אדם". It also says "ונתנה הארץ יבולה" - the earth will give "its" crop. The "יבול" relates to the earth because that growth of the fruits is a law of nature that is connected to the earth. "יבולה". And further "ועץ השדה יתן פריו" - the tree of the field will give "its" fruit. Again, the nature of the tree is to produce its fruit. פריו.
Then פסוק ה says that this crop will be sooooo bountiful, to the point that והשיג לכם דיש את בציר ובציר ישיג את זרע - Your threshing shall reach to the vintage, and the vintage shall reach to the sowing time. For that is what happens when nature is healthy, unblemished and unhindered.The pasuk further says "ואכלתם לחמכם לשובע" - You will eat your bread and be satiated, which Rashi explains to mean that you will eat a small amount and that will be enough for you because "it will be blessed in your stomach". Again, when nature is conducting as it is supposed to, then even a small amount of food suffices for each person. The reason people need to eat so much is because of a קלקול בטבע - a corruption of the natural order.
This is actually explicit in the Toras Koahnim which says on the pasuk "ונתנה הארץ יבולה ועץ השדה יתן פריו" that the earth will produce not as it does now but as it did in the time of אדם הראשון. So like we said, nature will be restored to its original pure form. The Gra in his commentary to Mishnayos Tomid [7-4] quotes the Zohar that the song of Yom Rishon is "לה' הארץ ומלואה", which corresponds to the first 1000 years of creation when the earth was "מלואה" - in its fullest form, until the מבול came and destroyed everything. That also explains the rest of the brachos - peace, no evil animals doing harm etc. All a result of nature being restored to its original pristine state.
Then we arrive at פסוק ט where it says "ופניתי עליכם" - which Rashi explains to mean that I will turn away from all my dealings [עסקי] to pay your reward. What are Hashem's dealings?? NATURE!! Hashem says that I will stop doing things my normal way and start conducting the world in a supernatural fashion. "ופניתי" comes from the word פני- פנימיות, the inner workings. At this point the true, miraculous inner workings of the world will be visible to all. As a result, והפריתי אתכם - LOTS of kids [like 6 in one shot], והרביתי אתכם - which means that you will go "בקומה זקופה" - with an upright posture. The Toras Kohanim later in פסוק י"ג explains that this means that you will fear no one. The idea is as the Gemara says [Chagiga 16a] that the angels go בקומה זקופה and people are similar to them in this trait. So we see that קומה קופה is supernatural and angelic.
Then the pasuk says "והקימותי את בריתי אתכם" which Rashi explains to mean that unlike the first covenant, this second one will not be revoked. The reason is that now you are above nature and its pitfalls, so you won't sin and thus this new ברית will last forever.
Now we arrive at 'פסוק י that says "ואכלתם ישן נושן וישן מפני חדש תוציאו" which adds on to the bracha of "והשיג לכם דיש את בציר". If earlier the nature of the world was such that you will have great bounty "that there will be plenty of threshing-work so that you will be busy with it till the vintage, and with the vintage you will be busy till the time of sowing" [as Rashi says] now the bracha relates to the PERSON. "This involves a promise that the fruits (grain) will be fit to keep the whole year and will even be of such good quality as to become old, so that the old grain that has grown old, that which is in its third year, will be better for food than that of the last year" [Rashi]. In other words, even though as far as the food is concerned, the food of the third year is not as good as the food of the previous year, in your merit it will be and YOU will eat the older produce. "ואכלתם ישן נושן".
That food retains it freshness not because of the quality of the food but because of the merits of those eating it is CERTAINLY supernatural.
We can explain the rest of the Parsha according to this approach. I hope to continue.
[עפ"י תורת מו"ר הגאון הגדול רבי ד"י מן זצ"ל]
