Another way: let the flock fertilize the field
A pen of two beis se'ah
Beis se'ah50 × 50 amos
Beis sasayim100 × 50 amos
Pen them, then move three walls — keep the middle one
General rulemakes a pen the size of two beis se'ah, uproots three sides and leaves the middle one. He is thus found to manure [an area of] four beis se'ah.
How much of the field, in all?
Tanna KammaA four-se'ah space→ four beis se'ah: 100 × 100 amos (two pens)
Rabban Shimon ben GamlielAn eight-se'ah space→ eight beis se'ah: 200 × 100 amos (four pens)
His whole field is only four beis se'ah?
leave a part unpenned — so no one thinks he is fertilizing
Restrictivehe must leave over
Reasonbecause of appearance's sake,
Then carry the manure out into heaps
Permissiveand he takes from the pen and places [it] onto his field in the manner of those who manure:
He must take it out
Rambam: he may take it out
Sheviis 3:4
Animal Pens
הַמְדַיֵּר אֶת שָׂדֵהוּ
הַמְדַיֵּר אֶת שָׂדֵהוּ, עוֹשֶׂה סַהַר לְבֵית סָאתַיִם, עוֹקֵר שָׁלֹשׁ רוּחוֹת וּמַנִּיחַ אֶת הָאֶמְצָעִית.
נִמְצָא מְדַיֵּר בֵּית אַרְבַּעַת סְאִין.
רַבָּן שִׁמְעוֹן בֶּן גַּמְלִיאֵל אוֹמֵר, בֵּית שְׁמוֹנַת סְאִין.
הָיְתָה כָל שָׂדֵהוּ בֵּית אַרְבַּעַת סְאִין, מְשַׁיֵּר מִמֶּנָּה מִקְצָת, מִפְּנֵי מַרְאִית הָעַיִן, וּמוֹצִיא מִן הַסַּהַר וְנוֹתֵן לְתוֹךְ שָׂדֵהוּ כְּדֶרֶךְ הַמְזַבְּלִין: